Various DOT-type devices for printing on surfaces are known, including electromagnetically driven devices, but in relation to the present invention the following U.S. Patents are noted:
U.S. Pat. No. 3,640,214 to H. J. Scheinhutte, 2-8-72, disclosed a printing system in which sparking is used to raise chamber pressure and thereby to eject ink at pre-selectable times and locations;
U.S. Pat. No. 4,128,345 to J. F. Brady, 12-2-78, disclosed a printing system in which tubes are used for selective printing action employing hot air or ink or plunger type pins and pressure change;
U.S. Pat. No. 4,279,519 to Schiurila, 7-21-81, disclosed a system in which ink is ejected at a projection for printing a dot in a matrix.